Reading texts with instructional pictures (text-picture integration) is a key component of students' learning processes in most school subjects, and teachers are tasked with helping their students acquire and refine this skill. The present study focuses on how teachers support their students with this process, and if this support contributes to improved text-picture reading skills. Analyzing self-reports of 56 science and German teachers at secondary schools, we found that the self-reported frequency of using text-picture reading material and the explicit discussion of the instructional picture affected students' skill improvement positively in the science, but not in the German classes. The self-reported teachers' efforts to guarantee all students' understanding of the pictures had no significant effect on students' skill improvement, however. A Matthew effect for students with higher prior text-picture reading skills was observed. The findings suggest that more research on teachers' instructional strategies in this important area of daily school activity in most subjects is needed to further understand how the impact of teachers on students' learning can be improved. Possible research directions are discussed.